Fiberboard containers formed from a single blank of fiberboard and having a cover panel foldable to a closed position over the top thereof are known. U.S. Pat. No. 3,889,868 discloses a container having such a top closure.
However, there are no known prior art containers of such a type which are closed in such a way as to prevent the closure panels from being easily opened to obtain access to the contents of the container. There is a need for such a container of tamper-proof construction for use in mailing and shipping valuable articles.